Answer:
Gene therapy is a medical field which focuses on the utilization of the therapeutic delivery of nucleic acids into a patient's cells as a drug to treat disease.
Answer:

Explanation:
The phospholipid bilayer is also known as the cell membrane. It covers cells and regulates the transport of substances. Certain ones can pass and others cannot, depending on certain factors like size and polarity.
Smaller substances tend to diffuse or move across the membrane quite easily. However, larger molecules have a much harder time. Many depend on special proteins embedded in the membrane. These are called transport proteins and they form a channel so large molecules can still move in or out of the cell.
So, salt, water, and fats do not contribute to the movement of larger molecules, but <u>channel or transport proteins do and choice A is correct. </u>
Mr. Turner, my American history teacher, taught us about the U.S. home front during WWII. Enjoy!
Answer:
<em>The correct option is A) an increase in oxygen levels, which led to the extinction of many anaerobic organisms.</em>
Explanation:
Photosynthesis can be described as a process in which food (glucose) is produced by photosynthetic organisms by using carbon dioxide, water along with light energy from the sun. Oxygen is released as a by-product of this reaction. The process of photosynthesis initially allowed for oxygen gas to get accumulated in the air. This caused the rise of aerobic organisms who required oxygen for respiration. Before the photosynthesis organisms evolved, there was not enough oxygen gas on earth to support the life of aerobic organisms.